Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

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Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
//package cf816;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.util.ArrayList;
import java.util.StringTokenizer;

public class C {
	static int a[][], N, M;
	static ArrayList<Integer> r, c;
	public static void main(String[] args) throws FileNotFoundException {
		InputStream is = System.in;
//		is = new FileInputStream(new File("A.txt"));
		FastScanner sc = new FastScanner(new InputStreamReader(is));
		r=new ArrayList<Integer>();
		c=new ArrayList<Integer>();
		N = sc.nextInt();
		M = sc.nextInt();
		a=new int[N][M];
		for (int i=0; i<N; i++)
			for (int j=0; j<M; j++) a[i][j]=sc.nextInt();
		if (N<M) {
			row(); col();
		} else {
			col(); row();
		}
		for (int i=0; i<N; i++) 
			for (int j=0; j<M; j++) 
				if (a[i][j]>0) {
					System.out.println(-1);
					System.exit(0);
				}
		System.out.println(r.size()+c.size());
		for (int rr:r) {
			System.out.println("row "+(rr+1));
		}
		for (int rr:c) {
			System.out.println("col "+(rr+1));
		}
	}

	static void col() {
		for (int i=0; i<M; i++) {
			int min=1001;
			for (int j=0; j<N; j++) {
				min=Math.min(a[j][i],min);	
			}
			for (int j=0; j<N; j++) a[j][i]-=min;
			while(min-->0) c.add(i);
		}
	}

	static void row() {
		for (int i=0; i<N; i++) {
			int min=1001;
			for (int j=0; j<M; j++) {
				min=Math.min(a[i][j],min);	
			}
			for (int j=0; j<M; j++) a[i][j]-=min;
			while(min-->0) r.add(i);
		}
	}

	static class FastScanner {
	    BufferedReader br;
	    StringTokenizer st;

	    FastScanner(Reader in) {
	        br = new BufferedReader(in);
	    }

	    String next() {
	        while (st == null || !st.hasMoreTokens()) {
	            try {
	                st = new StringTokenizer(br.readLine());
	            } catch (IOException e) {
	                e.printStackTrace();
	            }
	        }
	        return st.nextToken();
	    }

	    int nextInt() {
	        return Integer.parseInt(next());
	    }
	}

}